The present invention relates to a process for forming metal thin-film micropatterns on a plastic substrate by way of transferring metal micropatterns formed on an inorganic substrate to a plastic substrate.
Microchip devices, which have been used to perform liquid phase separations, e.g., electro-chromatography and electrophoresis, and to mix reagents in an integrated micro-reactor for chemical reactions, have many advantages over conventional bench-scale instruments in terms of increased speed of analysis, reduced reagent consumption, and amenability to automation through computer control. These integrated devices are now being referred to as a xe2x80x9clab-on-a-chipxe2x80x9d, as the operations of a complete wet chemical laboratory can be integrated on a chip.
A lab-on-a-chip conventionally comprises a number of micro-channels formed on a glass, silicon or plastic substrate, through which fluids are delivered. Recently, the plastic lab-on-a-chips have been favored, and therefore, many attempts have been made to develop a convenient and economic method for manufacturing plastic lab-on-a-chips.
Typically, the micro-pattern formed on a glass or silicon substrate is prepared by a process which comprises a metal deposition step followed by a photolithography step. When a plastic substrate is used, it is difficult to form a metallic micro-pattern directly on the surface of the plastic due to its high thermal expansion coefficient, sensitivity to organic solvents and weak interaction between plastic surface and metal pattern, and accordingly, a screen-printing or electroplating method has conventionally been used (see U.S. Pat. No. 6,030,515).
However, the screen-printing or electroplating method has disadvantages in that it is difficult to control the thickness or to reduce the line width of the micro-pattern to below a mm unit, and the surface of the micro-pattern formed has low adhesion to another plastic substrate, making it difficult to fabricate a plastic lab-on-a-chip system.
Therefore, there is an existed need to develop an improved method for forming a metal micro-pattern on a plastic substrate so that the fabrication of a plastic lab-on-a-chip system can be facilitated.
Accordingly, it is a primary object of the present invention to provide a novel and convenient process for forming a metal micro-pattern on a plastic substrate.
Further more, it is an object of the present invention to provide a process for the mass production of a plastic lab-on-a-system using a plastic substrate having a metal micro-pattern formed by the inventive process.
In accordance with one aspect of the present invention, there is provided a process for forming a micro-pattern of a metal on a plastic substrate, which comprises forming a metal micro-pattern on the surface of an inorganic substrate, surface-treating the surface of the metal micro-pattern or the surface of the plastic substrate to make it chemically reactive, and bringing the metal micro-pattern into contact with the surface of the plastic substrate to transfer the metal micro-pattern from the surface of the inorganic substrate to the surface of the plastic substrate.
In accordance with another aspect of the present invention, there is provided a micro-structured article prepared by plating the metal micro-pattern formed on a plastic substrate according to the inventive process with a conductive metal, which can be used as a free-standing metal micro-structure or a mold for the production of other micro-structured articles.
In accordance with further aspect of the present invention, there is provided a plastic lab-on-a-chip system fabricated by coupling a plastic substrate having a metal pattern formed according to the inventive process with another plastic substrate.